Question

The national centre of health statistics reports that the mean systolic blood pressure for males 35-44
years of age is 128 and a standard deviation of 15. A group of 50 executives selected at random are tested and found to have an avarage of 132.3. Is there statistical evidence that the executives have a different blood pressure than the population? Use significant level of 0.05. Solve using a confidence interval approach or a hypothesis test.

Answer 1

If you use a one-sample z-test, here is the formula:

z = (sample mean - population mean)/(standard deviation divided by the square root of the sample size)

With your data:
z = (132.3 - 128)/(15/√50) = ?

Finish the calculation.

Check a z-table at 0.05 level of significance for a two-tailed test.
If the z-test statistic exceeds the critical value from the z-table, reject the null. If the z-test statistic does not exceed the critical value from the z-table, do not reject the null.

I hope this will help get you started.